The perineal body (central tendon of the perineum) is a fibromuscular pyramidal structure approximately 3-4 cm anterior to the anal verge at the centre of the perineum. It is the convergence point for: the superficial and deep transverse perineal muscles, the bulbospongiosus bilaterally, the external anal sphincter anteriorly, the external urethral sphincter, and smooth muscle from the rectovaginal or rectoprostatic fascia. It acts as the central anchor of the perineal floor.
Serves as the central structural anchor of the perineum, integrating the muscular and fibrous components of the pelvic floor at its convergence point and maintaining the integrity of the rectovaginal or rectoprostatic septum.
The perineal body is the key surgical structure in obstetric perineal laceration repair, where its disruption (third and fourth degree tears, or episiotomy) must be meticulously reconstructed to restore pelvic floor integrity and prevent long-term prolapse and incontinence. Perineal descent syndrome involves thinning and descent of the perineal body from chronic straining, contributing to rectal prolapse and perineal pain. Surgical procedures for rectovaginal fistula and vault prolapse reconstruct the perineal body to restore the posterior compartment support.
Fourth degree obstetric tears disrupt the perineal body completely, tearing through the entire muscular and fascial convergence and exposing the anal sphincters, requiring careful identification and layered repair of each perineal body component: the fascia, transverse perineal muscles, and bulbospongiosus, before sphincter repair.
Chronic straining at defaecation causes progressive descent of the perineal body below the ischial tuberosity level during straining, producing a sense of incomplete evacuation, perineal heaviness, and eventual rectal mucosal prolapse from loss of anorectal angulation.
